Yahoo mail's security is a female canine from hell

I just lost my 18 year old email address thanks to the new improved security of Yahoo mail just because of I changed telecoms. Whenever I try logging in the one in the picture above appears. They want to make sure I am not some evil genius hacker so they want me to send verification to my alternate email. Here is the twist, I don't remember what my alternate email is because I havent used for like a decade.
I decided to check my alternate emails to my gmail accounts and attached them to my mobile number so they wont have the same fate with my Yahoo account. I am sorry Yahoo but I won't make a new account.

I really need to get rid of my yahoo, but there are a couple problems. 1. yahoo was my first account, so you can imagine the e-mails I have and wants to save. 2. It is connected to my Facebook and I don't know if I am able to switch e-mails and I really hate to create a new Facebook account.

@CaptAlbertWhisker I remember when my yahoo was compromised and whoever did it also somehow changed the sercurity code. It took a long time, but I soon got my account back and since then it has been compromised various time and the passwords are not only difficult, but I change the theme so often, it has to be another issue with the site.

@CaptAlbertWhisker I have several emails. Perhaps for better security you could try one I like a lot GMX mail. There is you have more than one email you can add them all in one site. Makes things much easier.

Your discussion made me check my Yahoo account. I discovered that the alternate email that I added didn't exist anymore (my account is 11 years old) I changed it and added an email that currently use. If I hadn't seen your discussion I could have ended up in the same situation as you. I hope that there is way that you can recover your Yahoo account, it is really frustrating to lose such an old account with many important things.